C++ : How can I push values into a vector only if that value isn't stored in the vector already?

Question

If for example, I was just pushing 200 random numbers into a vector, how can I ensure that duplicates will not be pushed in?

Answer 1

You need to check if the vector already contains the value, if not the push new value, i.e.

std::vector<int>::iterator it;
it = find (myvector.begin(), myvector.end(), newvalue);
if (it == myvector.end()) {
    // newvalue is not found
}

But this could be costly since find method would be checking every value inside myvector. Instead using set or map data structure can be more efficient.

Answer 2

seems like a map could be a helpful structure instead of a Vector. If you must stick to a Vector then you need to divide your task into two parts; duplication detection and then insertion. Again, your could insert into a map and then read that out into the Vector. In either case the problem is - intrinsically - two problems. Good luck!